Predictors of delirium in older patients at the emergency department: a prospective multicentre derivation study

Objective The objective of this study was to identify the predictors of incident delirium in this high-risk population. Methods This study was a planned sub-analysis of the INDEED multicentre cohort study. We recruited patients aged ≥ 65, independent/semi-independent, with an emergency department (ED) length of stay ≥ 8 h and admitted to any hospital ward. Patients were followed up during their ED stay up to 24 h after ward admission. Sociodemographic characteristics, comorbidities, functional status (OARS), illness severity, level of frailty, cognitive status (TICS-m) and ED/patient environment evaluation were collected during initial interview. Patients were screened for delirium twice a day using the Confusion Assessment Method. Multivariate logistic regression was performed to identify the predictors of delirium. Results Incident delirium was detected in 68 patients of the 612 patients included (11%). Initially, seven candidate predictors were included in a regression model, of which four were retained using a stepwise selection procedure. Presence of cognitive impairment at baseline (OR 3.6, p < 0.001), absence of mobilization during the whole ED length of stay (OR 3.3, p = 0.002), longer ED length of stay (OR 1.02, p = 0.006) were associated with a higher risk of incident delirium while higher functional status was associated with a lower risk (OR 0.8, p < 0.001). Conclusion More work is needed to determine which tool(s) are most appropriate for the ED use to increase delirium screening compliance among health professionals working in this department. It is really the first step to be able to suggest interventions to decrease delirium incidence.